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https://issues.apache.org/jira/browse/HBASE-10052?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13839769#comment-13839769
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Todd Lipcon commented on HBASE-10052:
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One thing to be wary of: _during_ the compaction, readers are still accessing
the old files, so if you're compacting large files, this could really hurt read
latency during compactions (assuming that people are relying on linux LRU in
addition to hbase-internal LRU for performance).
In most cases, as soon as the compaction is complete, we end up removing the
input files anyway (thus removing from cache), right? Or is that no longer the
case now that we have snapshots?
> use HDFS advisory caching to avoid caching HFiles that are not going to be
> read again (because they are being compacted)
> ------------------------------------------------------------------------------------------------------------------------
>
> Key: HBASE-10052
> URL: https://issues.apache.org/jira/browse/HBASE-10052
> Project: HBase
> Issue Type: Improvement
> Reporter: Colin Patrick McCabe
> Assignee: Andrew Purtell
> Priority: Minor
> Fix For: 0.98.0
>
>
> HBase can benefit from doing dropbehind during compaction since compacted
> files are not read again. HDFS advisory caching, introduced in HDFS-4817,
> can help here. The right API here is {{DataInputStream#setDropBehind}}.
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